1. Whole Numbers
Addition and Subtraction
What will we learn today?
• Addition of numbers up to 3
digits.

2. Here’s an addition example.

3. We have learnt this in the previous lecture.
5 0 5
tens
ones
hundreds

4. 505 + 104 = ___
5 0 5
+
1 0 4
9
Start your workings from the right.

5. 505 + 104 = ___
5 0 5
+
1 0 4
0 9
Start your workings from the right to left.

6. 505 + 104 = ___
5 0 5
+
1 0 4
6 0 9
Check your workings.

7. Test yourself.
90 = 8 tens and ____ ones
a) 1
b) 9
c) 10
d) 90

8. Test yourself.
90 = 8 tens and ____ ones
a) 1
b) 9
c) 10
d) 90
Ans: (c) because 10 ones make 1 ten.

9. Test yourself.
The sum of 230 and ____ is 610.
a) 180
b) 380
c) 420
d) 940
Hint: do working

10. Test yourself.
The sum of 230 and ____ is 610.
a) 180
b) 380
c) 420
d) 940
Ans: (b)

11. Are you ready to
try out the
questions?